1. Technical Field
The present invention relates to multi-level rotary switch, and more particularly, to a switch device able to be applied in various family electrical products with less electrical contact points, and increase durability by adjusting the pressure between the electrical contact points.
2. Description of Related Art
Switch is a necessary device in general electrical products, like machine tools and family electrical products, mostly used to control the electrical product to start and stop, or adjusting intensity of output circuit. Button switch and rotary switch are most general type of switch device. The button switch is mostly designed for simply controlling the electrical product to start and stop, and is rarely designed for adjusting intensity of output circuit. On the other hand, the rotary switch is mostly designed for adjusting intensity of output circuit. The intensity of output circuit can be adjusted by two general forms including controlling variable resistor and switching contact points.
Please refer to FIG. 1, shown an exploded view of conventional rotary switch. As shown in FIG. 1, a conventional rotary switch includes a rotary member 30P, a switch sheet 40P, and a main plate 50P, the rotary member 30P has a first spinning portion 31P on one side and a second spinning portion 32P on the other; the switch sheet 40P has a first conductive portion 41P, a second conductive portion 42P and a third conductive portion 43P, wherein the first conductive portion 41P locates on central of the switch sheet 40P, the second conductive portion 42P locates on one side of the switch sheet 40P and the third conductive portion 43P locates on the other. A first pivoting 44P is formed at the first conductive portion 41P, and providing the second spinning portion 32P to pass through, thus, the switch sheet 40P is able to position on the rotary member 30P. A second pivoting 51P is formed at central of the main plate 50P, and providing the second spinning portion 32P to pass through, thus, the second spinning portion 32P of the rotary member 30P is able to pivot on the main plate 50P with the switch sheet 40P. The main plate 50P further includes a main conductive unit 52P, a first conductive unit 53P, a second conductive unit 54P, a third conductive unit 55P and a fourth conductive unit 56P, wherein the main conductive unit 52P is made by conductive material, and disposed around the second pivoting 51P of the main plate 50P, thus, the switch sheet 40P contacts with the main conductive unit 52P when the second spinning portion 32P of the rotary member 30P pivots on the main plate 50P. The first conductive unit 53P, the second conductive unit 54P, the third conductive unit 55P and the fourth conductive unit 56P are all rectangle and made by conductive material, moreover, the first conductive unit 53P, the second conductive unit 54P, the third conductive unit 55P and the fourth conductive unit 56P are disposed on the main plate 50P.
The second conductive unit 54P is disposed between the first conductive unit 53P and the third conductive unit 55P, and opposite to the fourth conductive unit 56P. Due to the switch sheet 40P is restricted by the second spinning portion 32P of the rotary member 30P, the rotary member 30P pivots on the main plate 50P with the switch sheet 40P when the first spinning portion 31P of the rotary member 30P is rotated. During the rotation, the first conductive portion 41P of the switch sheet 40P keeps conducting to the main conductive unit 52P. The second conductive portion 42P of the switch sheet 40P conducts optionally to the first conductive unit 53P, the second conductive unit 54P and the third conductive unit 55P.
So that, through above descriptions, it is able to know that the constituting elements and the structure thereof of the conventional rotary switch, for more detail, switching of the conventional rotary switch also need to be introduced. During the switching of the conventional rotary switch, the first conductive portion 41P keeps conducting to the main conductive unit 52P, and the second conductive portion 42P of the switch sheet 40P conducts optionally to the first conductive unit 53P, the second conductive unit 54P and the third conductive unit 55P, that means, the switching of the conventional rotary switch needs at least four contact points to switch in each switch level. Please refer to FIG. 2A, shown a first switch level of the conventional rotary switch. The first conductive portion 41P conducts to the main conductive unit 52P, and the second conductive portion 42P conducts to the first conductive unit 53P, thus, the circuit supplied by AC power supplier only runs through first circuit A1, also, four contact points are used in first switch level of the conventional rotary switch including the first conductive portion 41P, the main conductive unit 52P, the second conductive portion 42P, the first conductive unit 53P. Please refer to FIG. 2B, shown a second switch level of the conventional rotary switch. The first conductive portion 41P conducts to the main conductive unit 52P, the second conductive portion 42P conducts to the second conductive unit 54P, and the third conductive portion 43P conducts to the fourth conductive unit 56P, thus, the circuit supplied by AC power supplier runs through first circuit A1 and second circuit A2, also, six contact points are used in second switch level of the conventional rotary switch. Obviously, the conventional rotary switch requests at least four contact points to operate. Under this request, it is clearly to know the first circuit A1 or the second circuit A2 cannot work normal if one contact point fails by worn, so the conventional rotary switch cannot be operate.
Moreover, the first conductive portion 41P and the second conductive portion 42P easily fail from fatigue after the conventional rotary switch is operated for a period, thus, the switch sheet 40P lost contact to the main plate 50P, and the switch sheet 40P cannot conduct to the main plate 50P if contact is lost, as the result, the conventional rotary switch cannot operate.
Accordingly, in view of the conventional rotary switch still has shortcomings and drawbacks, the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a multi-level rotary switch.